News

Growing Concerns over Liver Fluke Impact

ANALYSIS - Changing climates and higher rainfall in the UK are seeing the spread of parasitic pests that are costing the beef, dairy and lamb sectors millions of pounds each year.

Once only usually seen in the wetter western and north west areas of the UK, liver fluke has now become endemic in the UK spreading across the country.

Last year 16 per cent of all diagnosable conditions in cattle were liver fluke and according to Yorkshire vet Jonathan Statham, liver fluke has registered as number one in the top 10 diseases.

Speaking at the Veterinary Residues Committee open meeting, Dr Statham said that the distribution of liver fluke is determined by warm wet weather and recent flooding has brought with it increased disease risks.

He said that Fasciolosis caused by liver fluke (fasciola hepatica) is now a widespread parasitic disease of ruminant livestock and it has been increasing over the last decade in cattle and sheep.

Presenting a position paper from the Veterinary Residues Committee shortly to be published, he said that prevalence has been shown to have increased in England from 48 per cent in 2003 to 72 per cent in 2006/07.

Complex relationships exist between endemic diseases such as fasciolosis and food productivity.

The liver fluke can affect young stock and adult stock in beef and dairy herds and consequently greenhouse gas emission from the cattle sector are significantly increased relative to the production of milk or meat – a criticism of the sector that has already raised concerns since livestock production has been shown to be responsible for 17 per cent of greenhouse gas emissions from agriculture and agriculture accounts for seven per cent or total UK greenhouse gas emissions.

Controlling fasciolosis is critical in mitigating climate change impacts that have been associated with livestock production.

The disease has spread because of the prevalence and spreading distribution of the host to the fluke, the Galba snail that enjoys and breeds in wet muddy conditions.

Prevention from infections is either by preventing grazing in areas where the snail lives or through veterinary medicines. The four main products – closantel, clorsulon, triclabendazole and nitroxynil – having had a rough ride through the European veterinary medicines procedures for permitted residue levels and licensing.

However, Dr Statham said that treatment is necessary because of the damage the fluke can do to the animal and to productivity, including causing death in the case of sheep.

The Veterinary Residues Committee paper shows that carcase contamination because of liver fluke was reported at 19.81 per cent in 2010 – a total of 306,499 carcases, with an estimated loss of £1,225,996.

The English Beef and Lamb Executive estimates that liver fluke costs the UK beef industry between £8 million and £9.5 million a year with loses of productivity amounting to £25 to 30 for each case.

Production losses in infected dairy herds have been up to 2kg per cow drop in milk yield.

The disease can also reduce reproductive performance.

Dr Statham said that treatment with veterinary medicines is necessary but there is no blanket treatment and the measures have to be tailored for each farm.

And with an increasing number of cases of residues being found in milk and meat products there is a need to ensure accurate dosing.

“You need herd health management and to treat strategically with a flukicide,” said Dr Statham.

“There are different veterinary medicines for different stages of the fluke and this requires the cooperation of the farmer and vet.”

He added: “Flukicides are emerging as an increasingly important veterinary medicine.”